Update app.py

app.py

@@ -100,6 +100,9 @@ def predict_next_day(symbol, timeframe):
 
 def plot_candlestick(data, symbol, timeframe, predicted_price=None):
     """Plots the candlestick chart with technical indicators."""
+    if not isinstance(data, pd.DataFrame) or data.empty:
+        raise ValueError("No valid data to plot. Please check your inputs.")
+    
     fig, ax = plt.subplots(figsize=(12, 6))
     mpf.plot(data, type='candle', style='charles', ax=ax, volume=True, show_nontrading=True)